using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace CodePoint2UTF16
{
        public partial class Form1 : Form
        {
                public Form1()
                {
                        InitializeComponent();
                }

                private void btnConvert_Click(object sender, EventArgs e)
                {
                        String cp = tbUnicodeCodePoint.Text.Trim();

                        try
                        {
                                int n = Convert.ToInt32(cp, 16);
                                if (n < 0 || n > 0x10FFFF)
                                {
                                        MessageBox.Show(cp + " is not in 0x0 - 0x10FFFF");
                                        return;
                                }
                                if (n < 0x10000)
                                {
                                        tbUTF16Code.Text = Convert.ToString(n, 16);
                                        return;
                                }
                                else
                                {
                                        n -= 0x10000;
                                        int h = n >> 10;
                                        int l = n & 0x3FF;
                                        h |= 0xD800;
                                        l |= 0xDC00;
                                        tbUTF16Code.Text = Convert.ToString(h, 16) + " " + Convert.ToString(l, 16);
                                }
                        }
                        catch (Exception ex)
                        {
                                MessageBox.Show("Invalid text: " + cp + Environment.NewLine + ex.Message);
                        }
                }
        }
}